6-Methyl-3,4-methylenedioxyamphetamine (6-Methyl-MDA) is an entactogen and psychedelic drug of the amphetamine class. It was first synthesized in the late 1990s by a team including David E. Nichols at Purdue University while investigating derivatives of MDA and MDM.

6-Methyl-MDA has IC50 values of 783nM, 28,300nM, and 4,602nM for inhibiting the reuptake of serotonin, dopamine, and norepinephrine in rat synaptosomes. In animal studies it substitutes for MBDB, MMAI, LSD, and DOI, though not amphetamine, but only partially and at high doses.

Thus, while several-fold less potent than its analogues 2-methyl-MDA and 5-methyl-MDA, and approximately half as potent as MDA, 6-methyl-MDA is still significantly active,and appropriate doses may be similar to or somewhat higher than those of MDM.

3,4-methylenedioxy-methamphetamine is a synthetic drug that alters mood and perception (awareness of surrounding objects and conditions). It is chemically similar to both stimulants and hallucinogens, producing feelings of increased energy, pleasure, emotional warmth, and distorted sensory and time perception.

Molly was initially popular in the nightclub scene and at all-night dance parties ("raves"), but the drug now affects a broader range of people who more commonly call the drug Ecstasy or Molly.

Methylone substitutes for MDM in rats trained to discriminate MDM from saline. Methylone does not substitute for amphetamine or for the hallucinogenic DOM in animals trained to discriminate between these drugs and saline.

Further, also in common with MDM, methylone acts on monoaminergic systems. In vitro, methylone has one third the potency of MDMA at inhibiting platelet serotonin accumulation and about the same in its inhibiting effects on the dopamine and noradrenaline transporters.